Plasmacytoma

Aujame, L. Firko, H. (1988). The major inducible heat shock protein hsp68 is not required for acquisition of thermal resistance in mouse plasmacytoma cell lines. Mol. Cell. Biol. 8,5486-5494. 

Translation-competent ER membrane fractions can also be prepared from tissue culture cells. We recommend a terminally differentiated secretory suspension cell line, such as a plasmacytoma (e.g., J558L), which contains abundant levels of ER membrane. In this protocol, cells are collected by centrifugation (5 min, 500 x g) and resuspended in a homogenization buffer containing 10 mMKOAc, 10 mMK-HEPES, pH 7.5, 1.5 mMMg(OAc)2,... 

Multiple myeloma and extramedullary plasmacytoma (K2) diseases are now being reported in patients with AIDS and should be added to the list of neoplasms associated with HIV infection. 

The detection of monoclonality in immnnoglobnlin-producing neoplasms as mentioned above The presence of either, bnt not both, k or 7. light chain in lymphocytic proliferations may indicate the presence of a malignant neoplasm snch as B-cell lymphoma or myeloma/plasmacytoma. 

The benefit of the immunoperoxidase technique is best exhibited by the ability to detect neoplastic B cells. By demonstrating the presence of k or X (but not both) in lymphoid or plasma cells, one can establish a diagnosis of lymphoma or plasmacytoma. Unfortunately, in routinely processed tissue, only immunoglobulins in the cytoplasm and not on the cell surface membrane can be detected. 

Romanova LY, Alexandrov lA, Schwab G, Hilbert DM, Mushinski JF, Nordan RP (1996) Mechanism of apoptosis suppression by phorbol ester in IL-6-starved murine plasmacytomas role of PKC modulation and cell cycle. Biochemistry 35 9900-9906... 

In addition to these activities, IL-6 has been shown, in vitro at least, to regulate the growth and differentiation of various other cells — both normal and transformed. It inhibits the in vitro growth of human fibroblasts and endothelial cells. As both these cell types also synthesize IL-6, this may suggest the presence in vivo of a negative autocrine feedback loop (Figure 5.8). Plasmacytoma cells (transformed antibody-producing B lymphocytes), on the other hand, also secrete IL-6 and express and IL-6 receptor. In this case, however, the feedback loop is positive. 

Figure 5.8. Several cells secreting IL-6 also display IL-6 receptors on their surface, thus facilitating autocrine regulation by this interleukin. In the case of fibroblasts and endothelial cells, this regulation appears negative (inhibitory to cell growth). In the case of plasmacytoma cells, however, the autocrine loop is positive, with IL-1 stimulating further growth...

The development of hybridoma technology by Milstein and Kohler in 1975 revolutionized the antibody field and radically increased the purity and specificity of antibodies used in the clinic and for diagnostic tests in the laboratory. Hybridomas consist of antibody-forming cells fused to immortal plasmacytoma cells. Hybrid cells that are stable and produce the required antibody can be subcloned for mass culture for antibody production. Large-scale fermentation facilities are now used for this purpose in the pharmaceutical industry. 

Rat plasmacytomas are available, derived from the ileocecal lymph nodes of the LOU/C strain. The first rat-rat hybridoma was described by Galfre and coworkers in 1979 using the aminopterin sensitive line R210Y3.Agl.2.3 (Y3), which secretes immunoglobulin light chains. Further nonproducing rat myelomas YB2/0 and IR983F have since been derived. 

J558L Mouse plasmacytoma cell line Obtained from G Koch, MRC Laboratory of Molecular Biology, Cambridge, UK... 

Figure 2. R loops formed by mRNA from a K-producing plasmacytoma hybridized to DNA from the same tumor. An R loop is formed when mRNA hybridizes to the complementary DNA strand, displacing the sense DNA strand. In this example, two R loops are formed, one containing C and the other V region sequences. These two loops are separated by a double-stranded intron of -3.7 kb. The tail extending from the C region R loop presumably consists of the poly(A) segment of the mRNA. (Photograph reproduced with permission from Seidman and Leder, 1978 diagram modified from same figure.)...

---